1. Field of the Invention
The present invention relates to apparatus for positioning and controlling a suspended load. More particularly, this invention pertains to a gyroscopically-stabilized positioning system that is resistant to external forces.
2. Description of the Prior Art
Systems in a large number of endeavors employ hoist-and-payload arrangements. For example, I-beams and other structural elements are routinely moved into place while suspended from crane hoists. Cameras and grasping loads ("active" payloads) are lowered into mine shafts and otherwise-inaccessible locations for exploration and to aid in rescue and retrieval of persons and goods. Sea rescue efforts may employ cables suspended from helicopters for lowering rescuers and evacuating victims. Often, a stretcher is mounted at the bottom of the cable and the victim lifted while strapped down.
While hoisted loads enable exploration and rescue efforts from a remote platform, such efforts are often complicated and compromised by the flexible nature of the cable itself. Flexibility permits storage of substantial lengths of cable in limited spaces. However, operations may be compromised by the resultant lack of control over payload position and attitude. Elongated, flexible cables are readily subject to torquing that can result in spinning. Such torsion can be loaded into the cable through buffeting about by such external forces as wind, unintended contact with objects, etc. The very act of boarding a victim onto a stretcher will often produce this. The absence of control over the payload can be dangerous to the victim in the case of rescue efforts and can substantially compromise exploration by means of active suspended payloads.